Cotton fibers and method of treating same



p 1942- H. M. BUCKWALTER 2,297,536

COTTON FIBERS AND METHOD OF TREATING SAME Filed Dec. 31, I940 INVENTOR ATTO R N EY Patented Sept. 29, 1942 K COTTON FIBERS METHOD OF TREATING SAME Howard M. Buckwaltcr, Detroit, Mich, asslgnor to United States Rubber Company, New York, N. Y., a corporation or New .iersey Application December at, 1940, Serial No. 372,549

13 Claims.

This invention relates to improved cotton fibers, yarn, or cord, and a method of improving its tensile strength and resistance to heat deterioration at elevated temperatures.

In my copending application Serial 319,379, died February 17, 1940, of which this application is a continuation-in-part, I have described the present product, which results from a brief or monetary penetrating treatment of grey cotton, (that is, cotton fibers, yarn, cord, or fabric, containing substantially all of the natural cotton waxes)with a water-soluble relatively non-volatile, non-waxy, cotton-wax-peptizing agent of a character to provide retention of substantially all the original cotton waxes on the cotton yet allow fuller development of intrinsic fiber strength.

The term cotton waxes herein means that group or non-cellulosic water-insoluble components of the grey cotton which are characterized by extreme solubility in hot ethyl alcohol.

It has been found that as a result of such treatment, particularly with certain of-said agents, which is illustrated by the class of the alkali metal abietates or rosinates, that the grey cotton cords at 70 F. and 60% relative humidity show a tensile strength improvement on the order of to 15%, and higher, compared to the untreated grey cotton cords.

The so improved cotton in the form of yarn or cord, can be, but need not necessarily be, stretched or stretched and shrunk to substantially original length, to produce a still further improvement in tensile strength, as described in my said copending application. The unstretched chemically treated yarn or cord can however be employed as such, or combined with other processing, for the fabrication of various articles, for example, hose, tires, belting, and other strainresisting elements, and for the preparation of various fabrics, woven, knitted, or braided.

A preferred treating solution is Per cent by weight Water 86 Commercial ro in 6. 5 Collodial liquid sodium silicate (9.1% NazO; 29.6% $102) 7.5

In place of the sodium silicate, about 1% by to for simplicity, as an alkali-metal rosinatesilicate solution.

For the reason that not all of the various group of major importance is the hydroaromatic group to which the abietates or rosinates or other normally solid abietic acid derivatives belong, including the alkali salts of rosin which is mostly abietic acid, such as sodium or potassium rosinate, sodium or potassium abietate, correspending or other alkali salts of hydrogenated abietic acid, and corresponding or other alkali salts of abietic acid. This difference is demonstrated by the following table:

Table I Percent tensile Wetting time 2 fgf gg ga Chemical typo in 7% aqueous solution 60+ huthe cord mldity) l6 Instant Sodium roslnute-sillcatc. l2 ..do Sodium rosinste (technical). 4 ..do Sulphonated aromatic ether-alcohol (Triton W30). 4 bscconds Sodium all: 1 phcnylcno sulphonuto (Invadine 3 Instant Sodium alkyl naphthalene sulphonatc (NekalA 3 3 seconds Sodium alkyl-aryl sulphonato (N acconolNR). 2 Instant Butyl dlphcn sodium sulphate (Areskot 240). l ..do Sodium alkyl naphthalene sulphonato and solvents (Ncomcrpin VD). 0 ..do Algin soap compounds (Rcsolin NF). 0 do Bu phonated octyl alcohol (Lightening Penetrotor X). l ..do Sulgahonatedalkylhydrocarbon(Nopco l ..do Higll ier secondary alcohol sulphate (l ergitol Penetrant 7). 2 .do Su phonated esters of dlcarboxylic acids (Aerosol AY). -2 Zseconds Ollestersulfate (sllphntlccstcrsulfnto). 3 Instant Sulphonatod esters of dlcarboxylic acids (Aerosol 0'1). 4; 2seconds Hi hly sul honated castor oil Monosulph -5 Instant So uble pine oil (Nopco 1440). -6 10 seconds. hing) chain alcohol suliato (Dupcnol -6 do C H OONHC1H|SO NA(Igcponl). 8 lsecond Ltwifhain alcohol sulfate (Dupcnol il 2scconds IAilIZEfhBlIi alcohol sulfate (Duponol It is apparent from the above that as seven percent aqueous solutions, the chemicals produce a range of tensile changes from 12+ percent for sodium rosinate type to 9 percent for a long chain alcohol sulfate. That mere wetting tend to lubricate the fibers thereby reducing their intrinsic fiber strength. Therefore softening or plasticizing of the cotton waxes and thereby the fibers, would react against fiber tensile improvement. This may explain the lack of tensile improvement obtained with the aliphatic type of chemicals which definitely are not deplasticizing agents for the cotton waxes.

The hot ethyl alcohol extraction test is a convenient test for determining whether or not grey cotton has been treated with a deplastioizing wax-peptizing agent having the required properties. Untreated grey cotton usually gives on a fifteen minute extraction with hot ethyl alcohol, that is, an extraction of substantially all the alcohol-soluble material, a gain in fiber tensile strength on the order of 10 to due to the removal of the waxes, which as aforesaid when normally present on the fibers, tend to lower the intrinsic tensile strength of the fibers.

It should be understood here that such extrac-' tion methods although providing improved strength, have various objectionable features and are not suited for continuous processes. Washing and scouring treatments also remove the waxes but also remove water solubles whose presence is desired for improving resistance of the fibers or cord, to heat. By the short treatment of the present invention the natural water solubles are substantially retained with the cot-. ton-waxes which are distributed in association with the deplasticizing cotton-wax-peptizing agent.

In comparison, when grey cotton yarn or cord is treated by an abietic acid derivative of the present invention, the hot ethyl alcohol extraction of substantially all the alcohol-soluble material of the treated cotton produces less than 9% added improvement in tensile strength. This shows that by this invention, substantially all the natural cotton waxes remain but are changed on the fibers, by the said wax-peptizing agent, to a condition diflferent from their original condition. Otherwise they would have been removed by the solvent to the same extent as in the case of the untreated cotton. At the same time, the waxes are rendered almost,as ineffective in preventing the development of intrinsic fiber strength, as their total absence effected through solvent extraction. A deplasticizing cotton-wax peptiz'ing agent of this invention is therefore defined as one which when introduced into and onto grey cotton, is capable of providing, or serves to provide, on subsequent hot ethyl alcohol extraction of substantially all the alcohol-soluble material of the treated grey cotton, less than 9%, and preferably less than 5% gain in tensile strength of the cotton fibers.

This is illustrated in detail as follows:

A 3% solution of sulphonated castor oil took 5 seconds to wet cotton (25 C.) giving a tensile loss of -4%. When the treated cord was extracted with hot ethyl alcohol the percent tensile gain over the untreated cord was approximately 21%. A 3% potassium oleate solution wet instantly and gave 5% tensile loss and when extracted with hot ethyl alcohol, the treated'corcl showed a percent tensile gain of about 25%. Sodium naphthalene p-sulfonate gave a 1.4% increase in tensile and when alcohol extracted the treated cotton showed a tensile gain of 13.6%.

In comparison a sodium rosinate-silicate soiution (3% solids) gave a tensile gain of 11% and when the treated cotton was alcohol extracted, the gain was approximately 6%. A 9.8% rosinate-silicate solution gave a tensile improvement of about 15% and when alcohol extracted the percent gain in tensile in the treated cord was about 2.5 to 3%.

, humidity, a tensile improvement of at least about 10% in 8. treated 12.9/4/2 cotton tire cord. While the present treatment is not limited to any specific tire cord, the 12.9/4/2 construction is chosen as being a representative cord and all references herein to cord tires are based on this construction. Some of the characteristics of the 12.9/4/2 cord are, it is formed of American cotton, having a gauge of .033 inch, a tensile strength of 16.1 pounds at 70 F. and 60% relative humidity, a stretch at 10 pounds load of 12.5% and having a Weight represented as 1125 yards per pound.

The invention is of special utility in connection with the production of tire cord, from which tire cord, rubberized fabric plies are made, which in turn become part of the pneumatic tire carcass. By reason of the improved tensile strength of the unrubberized tire cord, it is possible to make a standard quality tire with less tire cord, or in the alternative to make a superior tire with the usual quantity of tire cord. Further, when the chemically treated grey cotton cords are, without intermediate drying. immersed in a rubber latex composition for the making of weftless cord fabric for tire carcasses, the consumption of the latex may be reduced 25 to 40%. The latex composition, when dry, ultimately acts to bind the cords in parallel relation.

Another advantage of the invention is the ability of the chemically treated grey cotton cord to withstand high temperatures for relatively long periods. This is beneficial in cords that form part of the carcass of a pneumatic tire which usually generates considerable heat during usage.

A preferred method .of treating grey cotton cords is described in connection with the accompanying drawing, in which:

Fig. 1 is a diagrammatic view of a cord treating process;

Fig. 2 is a diagrammatic detail view, in section, of a device for applying a solution to cords; and',-,

' Fig. 3 is a detail elevational view of a vacuum device for removing surplus moisture from the cords.

The cords may be treated individually; or a group of cords in parallel relation may be treated simultaneously; or the treatment may be applied to woven fabric. The illustration is concerned with a preliminary process in the making of a tire, whereby, as shown in Fig. 1, a cord, a group of cords, or a fabric sheet, iden ified by operations.

the reference character I, moves from a source of supply, engages a positioning roller 2, and passes downwardly in tangential contacting relationship to a supply pipe or tube 3 having a longitudinally extending slot 4 through which overflows a slight amount of an aqueous solution of a deplasticizing wax-peptizing agent, for example,

. the tube 3 rapidly so that only ohe side of the fabric composed of the parallel cords contacts with the solution in the V-shaped well 5. This causes an actual wetting of one surface of the fabric, and the solution penetrates the remaining portion of the fabric by capillary action. By

this arrangement a controlled and a minimum amount of a solution can be applied to the cords, and mechanical means to remove excess solution from the cords are reduced to a minimum. It is merely necessary for the cords to become wet with the treating solution and the wetting operation may be practiced at room temperature. The treatment of the cords is continuous and rapid; for example, good results have been obtained by wetting the cords at the rate of 15. yards per minute.

Referring to Fig. l, the cords, as they leave the tube 3 pass around a pair of pulling rollers 6 and i and thence downward to a movable tensioning roller 6 mounted on a pivoted arm 9. This roller is used merely to keep the cords taut. From this position the cords extend upward over a guide roller I0 and again downward where they are subjected to a water spraying operation from spray nozzles ii. Thereafter the cords move around a positioning roller i2 and upward into engagement with the water spray from additional nozzles i3, and through a pair of squeeze rollers It and i5 for removing excess water, which drains into the collector pan it. The cords are then moved around a roller ill to a substantially horizontal position and passed over a vacuum box I8 (Fig. 3) which consists of a chamber i9 communicating with a vacuum source and having a slot 29 extending transversely of the moving fabric. A roller 26 in combination with the roller I'd locates the cords l relative to the vacuum box l8. The vacuum box is an additional means to remove excess liquid from the cords. If desired, other means such as an air blast may be used in place of the vacuum box. a

Any variation in the positioning of these various semi-drying means may be made as desired. From the suction or vacuum box it the cords, which now have {the improved tensile strength, may pass to other desired processing For example, the cords may be rubberized to form fabric plies used in themanufacture of pneumatic tires, according to known practice.

By reason of the treatment above illustrated, there appears to be formed on or in the'cotton fibers a physical wax-rosinate complex, which can remain on the fibers with a slight excess of the treating compound. The treated cords usua ly finally contain, at least 75% of the original cotton waxes naturally occurring in grey cotton, and at least .5% by weight of the alkali rosinate or abietate. The increase in weight of the tire cord Whereas, workable concentrations of the waxpeptizing agent range from .5% by weight (based on the weight of the aqueous solution) to just short of the gelling or salting-out point which is around 15% concentration, preferred concentrations range from 2 to 10%.

While I have shown and described a method of treating finished tire cords, it is to be understood that the grey cotton fibers, yarn, plied yarn or cord may be treated at any of the various stages of the processing of the cotton..including treatment of the cotton prior to the formation of the'cord or any component part thereof. 3

The grey cotton fibers, yarn, or cord may be dipped in a water solution of the wax-peptizing chemical, or mixtures of such chemicals, or the solution may be made to contact the cotton as by a spraying operation. If desired, the treated cotton may be dried for storage or shipment.

The invention may be applied .to the treatment of grey cotton in various forms, e. g. unspun cot ton, yarns, plied yarns, cords, cabled yarns, twisted products from plied yarns, etc.

While rubberizing of the treated cotton has been referred to above as illustrative of further processing, it will be apparent that various uses of the grey cotton will not require rubberizing and that production of unrubberized fabrics including the treated cotton are also included within the broad scope of the invention.

Having thus described my invention, what I claim and desire to protect by Letters Patent is:

1. Grey cotton containing at least 75% of their original naturally occurring cotton waxes, said cotton containing by weight at least .5% of an. alkali salt of abietic acid.

2. A tire cord of improved tensile strength composed of grey cotton fibers which have been momentarily treated with an aqueous solution containing analkali metal abietate.

3. A tire cord of improved tensile strength composed of grey cotton fibers which have been momentarily treated with an aqueous "alkalimetal rosinate-silicate solution.

a. A method of improving the tensile strength of naturally occurring cellulosic fibers which comprises briefly treating yarns or cords composed of the native fibers having substantially their natural composition and structure with an aqueous solution of a relatively non-volatile water-soluble abietic acid derivative containing a tricyclic hydroaromatic condensed nucleus.

5. A process of improving the tensile strength of grey cotton yarn or cord which comprises briefly contacting said yarn or cord with an aqueous solution containing an alkali metal abietate and subsequently expressing the excess solution.

6. A pneumatic tire having a carcass containing cords of improved tensile strength composed of grey cotton fibers which havebeen momentarily treated with an aqueous alkali metal rosinate-silicate solution.

7. Grey cotton containing substantially all the original natural cotton-waxes modified by a short treatment of the cotton with a relatively nonvolatile non-waxy water-soluble cotton-waxpeptizing agent which contains a tricyclic hydroaromatic condensed nucleus and which is of a character that confers on the treated grey cotton the characteristic that it shows on hot ethyl alcohol extraction of substantially all the alcoholsoluble material a tensile strength improvement oi some but less than 9%.

densed nucleus and which is of a character that confers on the treated grey cotton the characteristic that it shows on hot ethyl alcohol extraction of substantially all the alcohol-soluble I material a tensile strength improvement of some but less than 9%. v

9. A tire cord formed of grey cotton fibers containing at least 75% of the original naturally occurring waxes and modified by a short treat ment of the fibers with a normally solid watersoluble cotton-wax-peptizing agent which is an abietic acid derivative of a character that confers on the treated cord the characteristic that it shows on hot ethyl alcohol extraction of substantially all the alcohol-soluble material a tensile strength improvement of some but less than 9%.

10. Grey cotton containing at least 75% of the original naturally occurring waxes and modified by a short treatment of the fibers with a normally solid watersoluble cotton-wax-peptizing agent which is an abietic acid derivative of a character that confers on the treated cotton the characteristic'that it shows on hot ethyl alcohol extraction of substantially all the alcohol-soluble material a tensile strength improvement of some but less than 9%.

11. Grey cotton containing substantially all the original natural cotton-waxes treated with a relatively non-volatile water-soluble abietat having the capability when applied to grey cotton as a 7% by weight solution in water, 01 providing, at 70 F. and relative humidity, a tensile strength improvement in the treated cotton over the untreated cotton of from about 10 to about 16%.

12. An article composed at least in part of grey cotton containing substantially all the original natural cotton-waxes treated with a relatively non-volatile water-soluble abietic acid derivativehaving the capability when applied to the grey cotton as a 7% by weight solution in water, of providing, at F. and 60% relative humidity, a tensile strength improvement in the treated cotton over the untreated cotton of from about 10 to about 16%.

13. An article composed at least in part of grey cotton containing substantially all the original natural cotton-waxes modified by a short treatment of the cotton with a relatively nonvolatile, non-waxy water-soluble cotton-waxpeptizing agent which contains a tricyclic hydro aromatic condensed nucleus and which is of a character that conferson the treated grey cotton the characteristic that it shows on hot ethyl alcohol extraction of substantially all the alcohol-soluble material a tensile strength im rovement of up to about 7%.

HOWARD M. BUCKWAL'I'ER. 

